Windows decades-old problem finally fixed! File Manager greatly sped up: deleting large files 30% faster

Microsoft has finally improved the speed of deleting large files in File Explorer in the Windows 11 Insider experimental preview build 26300.8935. Microsoft had promised a speed increase of at least 30% back in June, and now it has finally delivered.

The update log states: "In certain scenarios, deleting large fragmented files in File Explorer is now faster."

Although Microsoft only mentions specific scenarios, the improvement is most noticeable for users with nearly full disk space, as fragmented files are generated under such conditions.

Getting stuck on "Calculating" for a long time when deleting large files has been an old problem for Windows users for years, and the root cause is NTFS fragmentation.

When there is a large contiguous free space on the disk, NTFS usually writes files into a contiguous area, and deletion is quick; once the free space shrinks and breaks into scattered gaps, large files that continuously grow, such as virtual machine disks and databases, are split into thousands of small fragments scattered across the disk.

On HDDs, each fragment corresponds to a physical seek. A file split into thousands of pieces means the read head needs to move thousands of times to complete deletion. Although SSDs do not have physical movement, NTFS still needs to locate each fragment one by one and clear them from the free space record. Files with severe fragmentation can also slow down this process significantly.